Pisco Formation

The Pisco Formation is a geologic formation located in Peru, on the southern coastal desert of Ica and Arequipa. The approximately 640 metres (2,100 ft) thick formation was deposited in the Pisco Basin, spanning an age from the Late Miocene up to the Early Pliocene, roughly from 9.6 to 4.5 Ma. The tuffaceous sandstones, diatomaceous siltstones, conglomerates and dolomites were deposited in a lagoonal to near-shore environment, in bays similar to other Pacific South American formations as the Bahía Inglesa and Coquimbo Formations of Chile.

Pisco Formation
Stratigraphic range: Late Miocene-Early Pliocene (Tortonian-Zanclean)[1] ~9.6–4.5 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Lithology and sediments of the Pisco Formation across its allomembers
Type	Geological formation
Unit of	Pisco Basin
Overlies	Chilcatay & Caballas Formations
Thickness	640 m (2,100 ft)
Lithology
Primary	Tuffaceous sandstone, diatomaceous siltstone
Other	Conglomerate, dolomite
Location
Coordinates	15.7°S 74.5°W / -15.7; -74.5
Approximate paleocoordinates	15.8°S 73.8°W / -15.8; -73.8
Region	Arequipa & Ica Regions
Country	Peru
Extent	From Pisco to Yauca
Type section
Named for	Pisco
Outcrops of the formation in Peru

The Pisco Formation is considered one of the most important Lagerstätten,^[2][3] based on the large amount of exceptionally preserved marine fossils, including sharks (most notably megalodon), penguins, whales, dolphins, birds, marine crocodiles and aquatic giant sloths.

Famous fossils found in these layers include the giant raptorial sperm whale Livyatan,^[4] the aquatic sloth Thalassocnus,^[5] the sperm whale Acrophyseter, and the walrus-like dolphin Odobenocetops.^[6]

Description

The Pisco Formation of the Pisco Basin consists of tuffaceous sandstones, diatomaceous yellow to gray siltstones and a basal conglomerate.^[7] The formation is deposited from Pisco in the north to Yauca in the south. The northern portion is known as the Ocucaje Area and the southern part as the Sacaco Area.^[8] The total thickness of the formation is estimated at 640 metres (2,100 ft).^[9] The formation unconformably overlies the Chilcatay and Caballas Formations.

Paleobiota of the Pisco Formation

The Pisco Formation has provided a rich resource of marine fauna, including marine mammals like cetaceans and seals, large fishes, reptiles, and penguins.^[10] It is also one of the richest sites in the world for fossil cetaceans, with close to 500 examples being found in the formation.^[11]

The oldest fossils of the aquatic sloth Thalassocnus (T. antiquus) come from the Aguada de Lomas horizon of the Pisco Formation and were dated at roughly 7 Ma. The youngest specimen (T. carolomartini) was found in the Sacaco horizon and dated to approximately 3 Ma.^[12] Thalassocnus was preyed upon by the probable apex predators of the environment, Livyatan and megalodon.^[13][14] The youngest strata belonging to the formation have been dated at 2 Ma, corresponding to the Early Pleistocene (Uquian). Fossils of the Humboldt penguin were found in these deposits at the Yauca locality.^[15]

Birds

Taxa	Species	Locality	Materials	Description	Images	Notes
Spheniscus	S. humbodti	Sud Sacaco		Humboldt penguin		[15]
	S. megarhampus	Sud Sacaco	A partial skeleton	Banded penguin		[15]
	S. muizoni	Cerro la Bruja	A partial skeleton.	The oldest banded penguin		[16][17]
	S. urbinai	Sud-Sacaco West	A partial skeleton (partial skeleton with skull)	A larger banded penguin than S. muizoni		[15]
Ramphastosula	R. aguierrei			A sulid bird.		[18][19]
	R. ramirezi
Sula	S. brandi			A sulid bird.		[20][21]
	S. magna
	S. sulita
Morus	M. peruvianus	Sud-Sacaco		A sulid bird.		[20]
Perugyps	P. diazi	Sud-Sacaco	A limb element (right carpometacarpus).	A Cathartidae bird		[20]
Ciconiidae indet.	Gen. et sp. indet.					[22]
Fulmarus	Fulmarus sp.					[18]
Pelagornis	Pelagornis sp.					[23][24]
Pelecanus	Pelecanus sp.					[25]
Phalacrocorax	P. aff. bougainvillii					[18][26]
	cf. Phalacrocorax sp.

Fish

Bony fish

Taxa	Species	Description	Images	Notes
Alosinae	A. indet	A type of herring		[10]
Centropomidae	C. aff. Psamoperca	A snook fish		[10]
Triglidae	T. indent	A type of sea robin		[10]
Xiphiidae	X. ident	A sword fish		[10]
Sardinops	S. sp.	A sardine		[27]

Rays

Taxa	Species	Description	Images	Notes
Myliobatis	Indeterminate	A species of eagle ray		[10]

Sharks

Taxa	Species	Locality	Materials	Description	Images	Notes
Carcharias	C. taurus			The sand tiger shark		[18]
Carcharhinus	C. sp. indent			A requiem shark		[10]
Carcharodon	C. carcharias			The great white shark		[28][18]
	C. hubbelli
Cosmopolitodus	C. hastalis			The broad-toothed mako		[10]
Hexanchus	H. gigas			A cow shark		[28]
Isurus	I. oxyrhincus			The shortfin mako		[23]
Otodus	O. chubutensis					[10]
	O. megalodon			The largest of the megatoothed sharks (and of all fishes)

Mammals

Cetaceans

Taxa	Species	Locality	Material	Description	Images	Notes
Acrophyseter	A. deinodon	Sud-Sacaco	A skull	A small raptorial physeteroid		[20][29]
	A. robustus	Cerro la Bruja	A skull
Atocetus	A. iquensis	Cero la Bruja	A skull	A small toothed whale		[30][31]
Australithax	A. intermedia	El Jahuay		A long-snouted porpoise		[32]
Balaenoptera	B. siberi	Aguada de Lomas	A partial skeleton	A baleen cetacean		[23][33]
Belonodelphis	B. peruanus	Cerro la Bruja	A skull	A long delphinid		[23][30][34]
Brachydelphis	B. jahuayensis	El Jahuay	A partial skull	An early delphinid		[23][30][35][36]
	B. mazeasi	El Jahuay	A partial skull
Brujadelphis	B. ankylorostris	Cerro la Bruja	A skull with complete jaw	A river delphinid		[37]
Hemisyntrachelus	H. oligodon	Sud-Sacaco	A skull	An early form of orca		[18]
Incakujira	I. anillodefuego	Aguada de Lomas	A preserved skeleton	A small baleen cetacean		[23][38]
	I. fordycei	Aguada de Lomas	A preserved skeleton
Kogia	K. danomurai	Sacaco	A partial skull consisting of partial cranium, preserving the facial and dorsolateral regions of the cranial vault, but lacking most of the rostrum and basicranium	A basal member of the Kogia genus. Small physeteroid		[39]
Koristocetus	K. pescei	Aguada de Lomas	A partial skull	A small sperm whale		[40]
Livyatan	L. melvillei	Cerro Colorado	A partially preserved skull with teeth and lower jaw	An 18-meter long raptorial physeteroid with 36 centimetres (1.18 ft) teeth		[4]
Lomacetus	L. ginsburgi	Aguada de Lomas		A cetacean		[23][41]
Mamaziphius	M. reyesi	Cerros la Mama y la Hija	A partial skull consisting of partial cranium lacking most of the rostrum, the zygomatic processes of the squamosal, the occipital condyles and the ear bones	An early beaked whale		[42]
Miocaperea	M. pulchra	Aguada de Lomas	A partial skull	A cetothere whale		[43]
Ninoziphius	N. platyrostris	Sacaco	A partial skeleton	A giant beaked whale		[18]
Odobenocetops	O. leptodon	Sacaco	A preserved skull	A cetacean with dual tusks		[6]
	O. peruvianus	Sacaco	A partial skull
Piscobalaena	P. nana	Sud-Sacaco	A skull	A small baleen whale		[18][27]
Piscocetus	P. sacaco	Sacaco	A partial skeleton	An extinct cetacean		[28]
Piscolithax	P. aenigmaticus	Aguada de Lomas	A partial skeleton	A porpoise		[18][23]
Platyscaphokogia	P. landinii	Cerro Hueco la Zorra,	An incomplete skull lacking the tip of the rostrum and the basicranium.	An early beaked whale		[44]
Pliopontos	P. littoralis	Sud-Sacaco	A partial skull	An early delphinid		[18]
Scaphokogia	S. cochlearis	Aguada de Lomas		An extinct pygmy sperm whale		[23][45]

Pinnipeds

Seals

Taxa	Species	Locality	Material	Description	Images	Notes
Acrophoca	A. longirostirus	Sub-Sacaco	A partial skull.	A large pinniped thought to be the ancestor of the leopard seal		[18]
Australophoca	A. changorum	Aguada de Lomas	A partial skeleton consists of incomplete right ulna, right radius, right and left humeri, and other unidentified remains.	A phocidae seal.		[23]
Hadrokirus	H. martini	Sub-Sacaco	A partial skull	A species of true seal		[18][46]
Hydrarctos	H. lomasiensis	Sub-Sacaco	A skull.	An Otariidae seal.		[18]
Magophoca	M. brevirostris	Cerro la Bruja	A partial skeleton of a male.	A monachinae seal.		[47]
Piscophoca	P. pacifica	Sub-Sacaco	A partial skull	A phocidae seal		[27]

Xenarthrans

Sloths

Taxa	Species	Locality	Materials	Description	Images	Notes
Thalassocnus	T. antiquus	Aguada de Lomas	A partial skeleton including the skull, mandible, and most of the postcranial skeleton.	a semi-aquatic marine sloth		[5][18] [20][28] [48]
	T. carolomartini	Sacaco	An associated skull and mandible and two articulated hands, probably belonging to the same individual.
	T. littoralis	Sud-Sacaco	A skull with missing jugals.
	T. natans	Sud-Sacaco	A skull, mandible, and partial skeleton.

Mollusks

Bivalves

Taxa	Species	Description	Images	Notes
Dosinia	Indeterminate			[18]

Polychaetes

Taxa	Species	Description	Images	Notes
Diplochaetetes	D. mexicanus			[49]

Gastropods

Taxa	Species	Description	Images	Notes
Acanthina	A. obesa			[18]
	A. triangularis			[18]
Concholepas	C. kieneri			[18]
Herminespina	Indeterminate			[18]

Reptiles

Crocodilians

Taxa	Species	Locality	Materials	Description	Images	Notes
Eusuchia	Indeterminate					[18]
Piscogavialis	P. jugaliperforatus	Sacaco	A partial skeleton and a skull.	A gryposuchine gavialid crocodilians		[20][27]
Sacacosuchus	S. cordovai			A gavialid crocodilians		[50]

Turtles

Taxa	Species	Locality	Materials	Description	Images	Notes
Pacifichelys	P. urbinai			A sea turtle		[13][51]
Chelonia	Indeterminate					[10]

Correlations

Laventan

Laventan correlations in South America

Formation	Honda	Honda	Aisol	Cura-Mallín	Pisco	Ipururo	Pebas	Capadare	Urumaco	Inés	Paraná	Map
Basin	VSM	Honda	San Rafael	Caldera	Pisco	Ucayali	Amazon	Falcón		Venezuela	Paraná	Pisco Formation (South America)
Country	Colombia	Bolivia	Argentina	Chile	Peru			Venezuela			Argentina
Boreostemma
Hapalops
Miocochilius
Theosodon
Xenastrapotherium
Mylodontidae
Sparassodonta
Primates
Rodents
Birds
Terror birds
Reptiles
megalodon
Flora
Insects
Environments	Fluvial			Fluvio-deltaic		Fluvio-lacustrine		Fluvio-deltaic			Fluvial	Laventan volcanoclastics Laventan fauna Laventan flora
Volcanic	Yes

See also

• Bahía Inglesa Formation, contemporaneous fossiliferous formation of Chile
• Castilletes Formation, contemporaneous fossiliferous formation of the Cocinetas Basin, Colombia
• Cerro Ballena, contemporaneous fossil site of the Bahía Inglesa Formation of Chile
• Coquimbo Formation, contemporaneous fossiliferous formation of Chile
• Collón Curá Formation, contemporaneous fossiliferous formation of Patagonia, Argentina
• Honda Group, contemporaneous fossiliferous formation of Colombia
• Navidad Formation, contemporaneous fossiliferous formation of Chile
• Pebas Formation, contemporaneous fossiliferous formation of the Amazon Basin
• Urumaco, contemporaneous fossil site of the Falcón Basin, Venezuela